Universal Mobile Telecommunications System (UMTS) currently includes up to a ‘third generation’ (3G) mobile communications system developed within a framework known as IMT-2000 (International Mobile Telecommunications-2000). UMTS will play a key role in creating the mass market for high-quality wireless multimedia communications. UMTS will enable many wireless capabilities, delivering high-value broadband information, commerce and entertainment services to mobile users via fixed, wireless and satellite networks. UMTS will speed convergence between telecommunications, information technology, media and content industries to deliver new services and create revenue-generating services. Compared to its 2G or 2.5G wireless cellular counterpart, UMTS will deliver low-cost, high-capacity mobile communications with data rates on the order of 2 Mbit/sec under stationary conditions with global roaming and other advanced capabilities.
One drawback of the UMTS network is high cost of spectrum and low data rates as compared to WLANs (Wireless Local Area Networks). It is thus advantageous to complement UMTS with unlicensed band, high data rate WLANS such as IEEE 802.11 and ETSI Hiperlan2 to save UMTS radio resources and increase the efficiency of the UMTS RAN (Radio Access Network). Interworking may be provided between a WLAN hotspot and a radio access network such as UMTS to allow a user to utilize either the WLAN or the radio access technology, or both, depending on the location of the user. The interworking between the WLAN and the radio access technology may provide the user with roaming capability as the user moves between, and through, the coverage areas of the WLAN and the radio access technology in order to efficiently use the capabilities of the access networks.
Therefore, a need exists for a system and method, which utilizes WLAN bandwidth to supplement UMTS bandwidth to increase overall performance and efficiency. A further need exists for an architecture where the WLAN coverage area interacts with a UMTS network through an interworking function (IWF) that communicates with the UMTS Serving GPRS (General Packet Radio Services) Support Node (SGSN) as another SGSN over a Gn interface specified by the 3GPP standard body. Yet another need exists for a method for seamless interfacing of UMTS with WLANs through the use of interworking.